<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style>
    *{
      margin: 0;
      padding: 0;
    }
    img{
      width: 100px;
      height: 100px;
      border: 1px solid blue;
      position: absolute;
    }
  </style>
</head>
<body>
  <img src="xn.png" alt="">
  <script>
    var img = document.querySelector('img');
    var body = document.querySelector('body');
    document.onmousemove = function(e){
      img.style.top = e.clientY + 'px';
      img.style.left =  e.clientX + 'px';
    }
  </script>
</body>
</html>


